The present invention relates to an electrical generator and especially to a reciprocating generator attached to the underside of an ocean buoy that produces electric power responsive to movement of the buoy riding on an oscillating fluid.
Most methods for converting reciprocating energy into electric power involve systems to mechanically rotate a generator. They convert the motion of the ocean swells into linear motion of another fluid resulting in a loss of efficiency. These systems lose more efficiency during the step of converting the linear fluid motion into rotating turbine motion that drives the generator. Prior art wave generating systems also use wave motion to drive a hydraulic pump to force a fluid through a turbine connected to an electric generator.
One such prior art system uses wave motion to force air through hollow shafts and uses a by-driectional turbine placed in the air shaft to produce electric power. An oncoming wave forces air up the shaft and the receding wave sucks air back down the shaft. The air motion in the shaft then turns the turbine that drives the electric generator. In the Fredriksson U.S. Pat. Nos. 6,140,712 and 6,226,989, a Wave Energy Converter uses a tube attached to the underside of an ocean buoy. A reciprocating piston inside the tube pumps water up the tube to turn a turbine that turns a rotating generator. Each of these systems suffer from losses of efficiency in the process of converting wave motion into movement of a fluid and in turn uses the fluid motion to turn a turbine that turns a rotating generator.
The reciprocating generator power buoy of the present invention uses a linear generator that directly converts the vertical motion of ocean swells into electric power. This linear generator eliminates the conversion steps required to turn a standard rotating generator thereby eliminating the efficiency losses incurred by other systems. The reciprocating generator focuses a uniform magnetic field through the generator coil for the entire stroke of the generator. This design increases the efficiency of converting the energy in ocean swells and waves into electric power. The reciprocating generator consists of a permanent magnetic core that reciprocates with respect to a stationary coil that is annularly wound on a bobbin. The bobbin coil resides within a coaxial bore formed with a center pole flux core and an outer pole flux core on the exterior of the annular bore, both of which can be lined with permanent magnets. The arrangement of the magnets is in such a manner to create a uniform magnetic field of a single magnetic orientation throughout the entire length of the relative motion between the stationary bobbin coil and the magnetic core. The bobbin coil remains relatively stationary by means of damping plates attached to the bobbin coil that extend out and around the magnetic core. In addition, an electromagnetic winding mounted behind each permanent magnet receives a small portion of the electric energy generated by the relative motion between the magnetic core and the bobbin coil. This in turn increases the magnetic field within the coaxial bore, which increases the output of the reciprocating generator to the maximum energy available in the passing ocean swell.
A Reciprocating Generator Power Buoy generates electric power from the surface ocean swells. Damping plates attached to the generator coil maintain the coil in a stable position as the generator""s magnetic housing, solidly connected to the underside of an ocean buoy, reciprocates up and down with the passing ocean swells. A solid spacer between the buoy and the reciprocating generator locates the generator deep enough under the buoy such that the generator is in still water. This also inhibits the rocking motion of buoy allowing for vertical up and down motion. The magnetic housing focuses a magnetic field through the generator coil, creating an electromotive force in the coil from the relative motion between the coil and the magnetic housing. The magnetic housing consists of a center magnetic core and a series of outer magnetic cores. An end cap on both sides of the generator connects the center magnetic core to the outer magnetic cores. Electromagnetic windings enhance the initial magnetic field created with permanent magnets.